Postgresql 9.1中已存在關係「pk」

Question

我是Postgres/PostGIS的新手，目前正在使用PostGIS書籍。當我嘗試了其中一個示例的查詢時，出現以下錯誤消息，說明relation "pk" already exists。這是否意味着2個表不能使用相同的名稱進行約束？

查詢：

CREATE TABLE roads(gid serial PRIMARY KEY, road_name character varying(100)); 
SELECT AddGeometryColumn('public', 'roads', 'geom', 4269, 'LINESTRING',2); 

CREATE TABLE roads_NE(CONSTRAINT pk PRIMARY KEY (gid)) 
INHERITS (roads); 

ALTER TABLE roads_NE 
ADD CONSTRAINT chk CHECK (state 
IN ('MA', 'ME', 'NH', 'VT', 'CT', 'RI')); 

CREATE TABLE roads_SW(CONSTRAINT pk PRIMARY KEY (gid)) 
INHERITS (roads); 

ALTER TABLE roads_SW 
ADD CONSTRAINT chk CHECK (state IN ('AZ', 'NM', 'NV')); 

錯誤：

NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index "pk" for table "roads_sw" 


ERROR: relation "pk" already exists 

********** Error ********** 

ERROR: relation "pk" already exists 
SQL state: 42P07 

Answer 1

是。您需要在數據庫中使用不同的名稱